A network is a communication system that allows users to access resources on other computers and exchange messages with other users. A network is typically a data communication system that links two or more computers and peripheral devices. It allows users to share resources on their own systems with other network users and to access information on centrally located systems or systems that are located at remote offices. It may provide connections to the Internet or the networks of other organizations. The network typically includes a cable that attaches to network interface cards (NIC) in each of the devices within the network. Users may interact with network-enabled software applications to make a network request (such as to get a file or print on a network printer). The application may also communicate with the network software and network software then may interact with the network hardware to transmit information to other devices attached to the network.
A local area network (LAN) is a network that is located in a relatively small area, such as a department or building. A LAN typically includes a shared medium to which workstations attach and communicate with one another by using broadcast methods. With broadcasting, any device on the LAN can transmit a message that all other devices on the LAN can listen to. The device to which the message is addressed actually receives the message. Data is typically packaged into frames for transmission on the LAN.
FIG. 1 is a block diagram illustrating a network connection between a user 10 and a particular web page 20. This Figure is an example which may be consistent with any type of network, including a LAN, a wide are network (WAN), or a combination of networks, such as the Internet.
When a user 10 connects to a particular destination, such as a requested web page 20, the connection from the user 10 to the web page 20 is typically routed through several routers 12A-12D. Routers are internetworking devices. They are typically used to connect similar and heterogeneous network segments into Internetworks. For example, two LANs may be connected across a dial-up, integrated services digital network (ISDN), or a leased line via routers. Routers may also be found throughout the Internet. End users may connect to a local Internet service provider (ISP) (not shown), which are typically connected via routers to regional ISPs, which are in turn typically connected via routers to national ISPs.
If a router, such as router 12C, fails and is no longer able to route the desired connection, then the desired connection between the user 10 the desired web page 20 may be significantly delayed or unable to connect at all.
To avoid this problem, a solution has been implemented by router manufacturers, such as Cisco Systems, that include two processors, a primary processor and a secondary processor, such that the secondary processor may take over as the main processor if the primary processor has either a hardware or software failure. Accordingly, such a solution provides redundancy to avoid failure of the router.
Although this solution works well, it may be desirable for many companies to avoid buying a specialized router with built in redundancy and simply use their existing routers for the same purpose. The present invention addresses such a need.